US526483A - Art of treating plastic rubber compounds - Google Patents

Description

(No Model.)

W4. CABLR.' ARA1 0F TRRATINC PLASTIC RUBBER COMPOUNDS. No. 526,483. Patented Sept. 25, 1894.

WTRIEEEEE- NVE- NITEIR vn: nomas mens aa. PNomLm-xu. wAsmNnTou, o. cA

UNITED STATES PATENT OEEICE.

WHEELER CABLE, OF BOSTON, MASSACHUSETTS.

ART OF TREATI NG PLASTIC RUBBER COM POU N DS.

SPECIFICATION forming part of Letters Patent No. 526,483, dated September 25, 1894. Application filed August '7, 1893.1 Serial No. 482,533. (No specimens.)

To afZZ whom it' may concern.-

Beit known that I, WHEELER CABLE, of Boston, in the county ofSufEolk and State of Massachusetts, have invented a new and useful Improvement in the Art of Treating Plastlc Rubber Compounds, of which the following, taken in connection with the accompany-` lng drawings, is a specification.

' My invention is an improvement in the ar-t of treating plastic rubber compounds, and especially those wherein the rubber is largely or entirely such as is known as reclairned,` that is old rubberworked over.

Vast quantities of this stock are annually used, and for many purposes it is scarcely inferlor in serviceability to fresh gum, while its cost is but a small fraction of that of new rubber. Great care in treating it is, however, necessary, especially where it is to be subsequently spread thin to serve as a coating for woven or other fabrics, which are to be thereby rendered water-proof. For this purpose it has long been common to treat the compound in a calender, between the upper and middle rolls of which it passes in a very thin sheet,

so that the workman, scanning this sheet with quick, practiced eye, may remove, while it is passing downwardly on the middle rollerjany considerable particles of foreign matter, the presence of which in the compound would cause imperfections in the coating when subsequently spread. To remove these impurities it is absolutely essential that the plastic sheet shall be so thin that they are visible in it and may be picked out as the material passes. For practical success this should be done, without stopping the machine unneces` sarily. Right here a difficulty hithertoinsurmountable has arisen. The middle calender roll soon becomes materially heated, and the plastic sheet, having a thickness not much exceeding the hundredth part of an inch, clings to the roller surface, tending to follow it upwardly and again pass between the upper and middle rollers, thus clogging the machine or making it inoperative until stopped, and the roller cooled. This is because there is not sufcient tenacity in the thin sheet of this reclaimed rubber to pull it away from the roller; but if the sheet passes before the workmans eye with sufficient thickness to insure its removal freely from the roller he cannot see the `tween the lower rollers. `thickness gives to the sheet sufficient body most of theimpurities, and hence the stock will be of inferior quality and the coating subsequently applied to the fabric will be full of minute holes. My improved method solves this difficulty in a very simple manner, yet one that has hitherto eluded the thoughts of skilled workmen notwithstanding the urgent need of relief for many years. Instead of thickening the sheet where it passes for inspection before the workmans eyes, or attempting to remove itwhile so very thin, I double its thickness automatically after it has been inspected. To do this practically and conveniently I vgear the lower roller to run at about half the 'surface speed of the middle one, with which it is in close proximity, thereby causing the sheetto be transferred from the roller on which it was inspected to the surface of the lower roller and to be simultaneously about doubled in thickness owing to such reduction in speed and to the increased distance .y be- This increase in and cohesiveness to insure its ready separation from the roller surface. For this pur pose I provide a small deliveryroller in rear of the lower calender roller, and belted to it or otherwise driven atsomewhat higher speed so as to pull the sheet away from the calender. inspected on the middle calender roller and subsequently thickened, is delivered continuously without the slightest recurrence of the former difficulty.

The drawing is a transverse vertical section through a calender, furnished withmy From this small roller the rubber sheet,

supplementary roller, and adapted to the practice of my improved method.

A, B, C are the three cylindrical steel rollers, mounted in the usual bearings in the upright standard D of the frame,-the middle roller B being in fixed bearings and the rollers A and C capable of accurate adjustment toward and from it.

The plastic mass of rubber R under treatment is shown in the bight of the rollers A, B which are geared to turn with equal speed or the middle roller at a higher speed than the upper roller A. They are for my purpose, set very closely together, leaving only space for a sheet S about the hundredth part of an inch in thickness spread uniformly over a ICO The rollers -B and Care set about twice as4 far apart as the rollers A and B, and are geared together, the gear wheel on the lower roller having about twice as many'teeth as that on the middle roller so that the one shall revolve with about half the surface speed of the other. This difference in speed causes the rubber sheet S2 to part from the middle roller and move downwardly on the opposite Side of the slower roller O. Simultaneously with and in consequence of this change of speed the soft rubber sheet substantially doubles in thickness, the two rollers being far enough asunder to insure this.

Back of the lower roller C I mount the smalll delivery roller E in suitable bearings, and I cause it to revolve at a surface speed sufficiently faster than the roller C to overcome the stretch of the sheet, and to pull it free.` Thisl do by belting it to said roller C or by an interposed friction wheel F of proper diameter. This simple attachment pulls the thickened sheet S2 continuously from the roller O and deposits it on the platform, or otherwise, in folds or layers forming a plastic mass for subsequent treatment, the impurities having been detected and picked out while the compound was rolled down thin, andthe desired tenacity in the sheet enabling it to be removed alone, accompanying its thickening.

Under my improvement, with less manual labor than has heretofore been required, Ican turn -out daily, without any trouble, twice as much of :ther linished product-as-was practicable under the old system, with its waste of time and constant annoyance. The value of this improvement, as applied simply to the treatment of the millions of pounds of old rubber annually reclai-med, will be apparent.

I claim as my inventiont 1. The improvement in the art of treating plastic rubber com/pounds, which consists in spreading such material in a very thin sheet upon a moving surface, inspecting and removing impurities therefrom while so spread and moving,and then thickening said sheet .at its forward end and removing the thickened sheet from its carrying surface, substantially as and for the purpose set forth.

2. The improvement in the art 'of treating reclaimed rubber compounds, consisting in spreading such material in avery thin sheet, inspecting and removing impurities therefrom while so spread and moving forward, then transferring such material to a surface moving at a reduced speed, and simultaneously increasing the thickness of the sheetin acorresponding ratio, and subsequently removing the thickened sheet from said surface and depositing it in a mass, substantially as setforth.

3. The combination of the calender rollers A B, geared for moderate surface speed, with the lower calender roller C geared to run at about half vsaid speed, and with the supplemen tary delivery roller E driven at somewhat higher-speed and adapted to pull the thickened sheet of compound alone from such slow roller, substantially as and for the purpose set forth.

In testimony whereof I have signed my name to this speciiication,in the presence of two subscribing Witnesses, on this 30th day of March, A. D. 1893.

` WHEELER CABLE.

Witnesses JOHN C. LANE, L. E. TALMADGE.

Images